Diamond nib holder



Oct. 10, 1961 G. L. GROVE 3,003,492

DIAMOND NIB HOLDER Filed Jan. 12, 1959 ATTORNEYS.

United States Pater 3,003,492 DIAMOND NIB HOLDER George L. Grove, Cincinnati, Ohio, assignor to The Clucinnati Milling Machine Co., Cincinnati, Ohio, a corporation of Ohio Filed Jan. 12, 1959, Ser. No. 786,290

This invention relates to a holder for a diamond nib used in truing grinding wheels and, more particularly, to a holder provided with ducts surrounding the nib for conducting coolant to the diamond to bathe it with a cooling medium during truing operations. In addition, the holder may include a shield surrounding the end of the diamond nib for containing the coolant and pocketing it around the diamond so as to maintain the diamond submerged in the coolant during truing of the grinding wheel.

, In the past it has been customary to direct a spray of coolant from a nozzle onto the diamond nib during wheel turning operations in order to cool and lubricate the diamond. This arrangement, however, has not been entirely satisfactory where wide-faced wheels are concerned since the high velocity of the coolant spray is not conducive to carrying away the large amounts of heat developed during long cuts over wide-faced wheels. To provide better cooling, an effort was made to surround the diamond with coolant by drilling holes in the nib around the diamond and flowing coolant through these holes during the truing operation. This method, however, has the disadvantage that the holes must be of small diameter, due to the small size of the nib, thereby undesirably limiting the volume of coolant which can be supplied to the diamond by this method. Also, the small holes in the nib have been found subject to clogging by particles of grit and abrasive carried by the coolant which further limits the usefulness of this type of cooling arrangement.

The present invention has for its object the provision of means for supplying adequate coolant to the diamond at all times thereby preventing overheating and cracking of the diamond during extended cuts. For this purpose, a special diamond nib holder has been provided in which a plurality of ducts are circumferentially disposed in the holder around the nib for supplying coolant to the diamond in ample quantities to protect the diamond from overheating. By placing the coolant ducts in the holder in place of in the nib, it is possible to make the ducts of sufiicient diameter to eliminate the problem of clogging and, also to supply ample quantities of coolant to the diamond to protect it against damage. The placing of the ducts in the holder in place of in the nib has the further advantage that standard nibs may be used thereby eliminating the need for stocking a special type of nib. The invention also comprehends the provision of a shield on the holder surrounding the end of the nib for pocketing the coolant around the diamond to assist in the transfer of heat from the diamond to the coolant.

Accordingly, it is an object of the present invention to provide a diamond nib holder with a plurality of ducts circum-ferentially spaced around the nib for supplying coolant to the diamond during wheel truing operations.

Another object of the invention is to provide a diamond nib holder with a shield surrounding the end of the nib to maintain the diamond submerged in the coolant supplied through the ducts in the nib holder.

With these and other objects in view, which will become apparent from the following description, the invention includes certain novel features of construction and combinations of parts, the essential elements of which are set forth in the appended claim, and a preferred form or embodiment of which will hereinafter be described with 1 Claim.

reference to the drawings which accompany and form a part of this specification.

In the drawings:

FIG. 1 is a side elevation of a diamond truing bar to which the invention is shown applied.

FIG. 2 is a cross-sectional view showing, on an en'- larged scale, the constructional details of the present invention.

FIG. 3 is an enlarged view taken along the line 3-4 in FIG. 2 showing the arrangement of the coolant ducts in the nib holder.

Similar reference characters designate similar or identical elements and portions throughout the specification and throughout the dilferent views of the drawings.

To provide a proper understanding of the character of the invention and its mode of use, there has been shown in the drawings a diamond truing bar 10 (FIG. 1) of conventional design which is attached to a slide 11 which is in turn supported for rectilinear sliding movement on a base plate 12. The latter plate is secured to a bracket 13, attached to the frame of the grinding machine, to provide support for the truing bar in a Well known manner. The plate 12 is provided with a rib 14 which extends parallel to the axis of the grinding wheel 15 to be trued, and the slide 11 is provided with a mating groove for receiving the rib and holding the slide on the plate while guiding it for rectilinear sliding movement thereon. Traversing movements of the slide 11 may be efiected by a feed screw 16 which, when rotated, will cause travel of the slide in a well known manner.

The truing bar it includes a tubular housing 20 which is formed integral with or otherwise suitably attached to the slide 11. A hollow bar 21 is slidably received within the housing 20, and secured to the end of the bar 21 adjacent the grinding wheel 15 is a diamond nib holder 22. At its opposite end, the bar 21 is fitted with a nut 23 which meshes with a screw 2.4 journaled in an end cap 25. The outer end of the screw 24 has secured thereto a handcrank 26 to permit rotation of the screw and thereby effect axial feeding movement of the bar 21 within the housing 20.

As previously mentioned, the bar 21 is hollow, or channeled and coolant is delivered to the hollow interior of the bar, as defined by internal wall surface 27 (FIG 2), through a fitting 23. The inner end of this fitting is threaded into a tapped hole provided in the Wall of the bar 21, the leg of the fitting passing through a slot provided therefore in the housing 2% to permit axial movement of the bar 21 within the member.

As shown in FIG. 2, the diamond nib holder 22 is secured to the end of the bar 21 by cap screws 31 which pass through enlarged holes provided therefor in the holder 22 and thread into tapped holes provided in the end of the bar 21. The holder 22 has a neck portion 32 projecting therefrom which is provided with a socket 33 for receiving a diamond nib 34 of conventional design. A set screw 35 (FIG. 3) is provided in the neck 32 for engaging with a flat 36 formed on the nib 34 to hold the latter in place within the holder. In the end of the nib 34 is mounted a cutting diamond 37 which is efiective to trim abrasive material from the wheel 15 when the diamond is traversed over the surface thereof by means of the feed screw 16 associated with the slide 11.

Exact alignment of the diamond 37 with the center line 38 (FIG. 1) passing through the center of the grinding wheel, may be effected by loosening the cap screws 31 and turning a jackscrew 39 (FIG. 2) which is threaded into the holder 22 and bears against the upper cap screw 31 as shown in FIG. 2. After suitable adjustment of the holder has been made to bring the diamond onto the center line, the cap screws 31 may then be tightened to eausewashers 40 lying beneath the heads of the screws to frictionally retain the holder in its adjusted position. The flow of coolant from the interior of the bar 21 to the. diamond 37 is effected by a plurality of ducts 42:

which are circumferentially disposed around the nib as shown in FIG. 3. Each duct 42 extends longitudinally through the neck 32 and communicatively connects the outer end of the neck with the coolant chamber in the bar 21. Accordingly, when coolant is delivered through the .fitting 28 into the bar 21 it will be caused to, flow through the ducts 42 and surround the nib and the diamond 37" with coolant as the diamond is traversed across thesurface of the wheel 14.

It has been found that removal of theheat from the diamond 37 may be enhanced by pocketing the coolant around the diamond so as to submerge the latter in the coolant during wheel truing operations. For this purpose, the neck 32 may be provided with a shield portion 44 extending therefrom so as to form a pocket 45. for receiving the coolant flowing out through the ducts 42., In this way, the diamond 37 is actually submerged in a bath of coolant rather than being subjected to a stream or spray thereof. This complete submerging of the diamond in the coolant has been found to, provide a highly eflective means of removing the heat therefrom. Since, the surface of the grinding wheel being trued'serves to close onev side ofthe pocket, this method is most useful on long cuts across wide-faced wheels where the need for efiective cooling of the diamond is the greatest. However, with or without theshiel 44, the present type of diamond nib holder in which the coolant ducts are provided in the holder itself presents an advantage not heretofore realized since the ducts 42 may be made of ample size to support ra heavy flow of coolant to the diamond, and since a diamond nib of standard construction may be utilized with this type of holder.

While the present invention has been described in connection with one possible form or embodiment thereof,

it islto be understood that the. present disclosure is illustrative rather than restrictive and that changes and modifications may be resorted to without departing from the spirit of the invention as defined by the claim which follows.

What is claimed is:

A holder for supporting a diamond truing nib on the end of a truing bar having a longitudinally extending channel therein comprising a body portion, fastening means for attaching. the body portion to the end of the truing bar, a neck portion on the holder projecting outwardly from said body portion in the general direction of the axis ofthe truing bar, a socket in said neck portion for receiving the shank of the diamond nib, a plurality of ducts extending longitudinally through said neck portion and communicating with the channel in the truing bar for delivering coolant from the channel out through the end of said neck portion in surrounding relation to the, socket, and a peripheral shield portion, formed integrally with said holder and extending beyond the end of said neck portion in circumscribing relation to the ducts and. to the socket to form a coolant containing pocket for submerging. the diamond in coolant during truing operations.

References Cited in the file oi this patent UNITED STATES PATENTS 1,611,028 Harrison Dec. 14, 1926 2,082,418 Palmer June 1, 1937 2,254,393 Petrie Sept. 2, 1941 2,442,033 Brantley May 25, 1948 2,451,395 Klukan Oct. 12, 1948 2,644,442 Loecy July 7, 1953 2,858,652 Luthman Nov. 4, 1958 2,862,492 Bruce Dec. 2, i958 FOREIGN PATENTS 1,156,858" France- May 22, 1958 

